Is diurnal lifestyle altered during Ramadan in professional Muslim athletes?

Lifestyle and circadian patterns are disturbed in Muslims during the holy month of Ramadan. The aims of this study were to establish how the timing of sleep was influenced by fasting diurnal requirements and how training practices were altered in professional soccer players by comparing behaviour over the Ramadan month to that displayed in the four weeks immediately following. Altogether 20 players from a top professional club in an Islamic country were monitored for eight weeks. Environmental conditions were similar between the two periods. The players adjusted to the privations of Ramadan by altering bedtime to later at night and spending longer in bed than in the month following. Timing of sleep was delayed significantly during Ramadan, a mean delay in bedtime (199 ± 47 min) and an increase in sleep length (99 ± 42 min) being observed during Ramadan. The training load, as indicated by training impulse (TRIMP) scores, did not vary between Ramadan and the following four weeks, although the duration of training sessions was shortened after two weeks of Ramadan. Core temperature responses (38.4 ± 0.6 and 38.5 ± 0.7°C) to training and fluid losses were similar between the two four-week periods. Fluid intake (r = 0.81; P < 0.05) and fluid loss (R = 0.76; P < 0.05) were significantly correlated with TRIMP scores. Urine osmolality (825 ± 143 mOsmol/kg H2O) was higher during Ramadan compared to the reference period that followed (708 ± 155 mOsmol/kg H2O); there was also a significant difference during the weeks of Ramadan (F 3,27 = 3.42; P < 0.05), pair-wise comparisons revealing a significant difference (P = 0.038) between week 1 and week 4, a mean reduction of 159 mOsmol/kg H2O. The results demonstrate how these players responded to the fasting requirements of Ramadan and cannot be generalised to non-professional athletes or individuals adopting more devout programmes.